A Ti2N MXene-based nanosystem with ultrahigh drug loading for dual-strategy synergistic oncotherapy.

The exploration of MXenes, especially nitride MXenes, in the field of theranostic nanomedicine is still in its infancy. Here, towards synergistic chemo-photothermal oncotherapy, we demonstrate the first kind of 2D titanium nitride (Ti2N) MXene-based nanosystem (Ti2N@oSi) for dual-strategy synergistic oncotherapy. The unique structure of Ti2N nanosheets endows the drug carriers with an ultrahigh loading capacity of 796.3% and an excellent NIR photothermal conversion efficiency of 41.6% for chemo-photothermal therapy. After being coated with a biodegradable organosilica shell, the Ti2N@oSi nanocarriers show excellent characteristics of tumor targeting, pH/glutathione/photothermal-responsive drug release and dual-drug combination chemotherapy. Both in vitro and in vivo therapeutic evaluations demonstrate the pronounced tumor growth inhibition effect and superior biocompatibility of Ti2N@oSi nanocarriers. The excellent drug loading ability, photothermal conversion ability and surface modifiability of Ti2N open up new opportunities for tumor microenvironment-targeted synergistic oncotherapy. This work is supposed to broaden the application of MXenes in nanomedicine and, particularly, provide the first sight to the biomedical application of nitride MXenes.